The following disclosure generally relates to medical devices.
Vascular disease, the disease of blood vessels, is one of the leading causes of death in the western world. There are two main categories of vascular disease, aneurysmal and occlusive. Aneurysmal disease results in the weakening of blood vessels causing them to dilate excessively and in some instances ultimately rupture. Occlusive disease results in blockage of blood vessels, limiting the conveyance of blood.
Balloon dilation is a commonly used treatment for blood vessels ravaged by occlusive disease and for other tubular structures within the body suffering from a variety of maladies. Balloon catheters have been employed successfully to radially open various bodily conduits. In the treatment of occlusive vascular disease, balloon dilation of blood vessels (angioplasty), remodels the inner surface of the blocked vessels, restoring blood flow. Additionally, balloon dilation is practiced in other bodily conduits such as the urinary tract, the bile duct, tear ducts, nasal and sinus passages and the tracheo-bronchial tree.
Currently, it is common procedure to combine site specific drug therapy with balloon dilation. To such ends, balloon catheters are equipped with various means for the conveyance of therapeutic agents to a site of disease. Some devices include channels through which a liquid drug can be delivered. In some cases, unique compositions of drugs are applied onto the balloon surface and are conveyed to the site of disease by direct contact during the balloon dilation.
Regardless of the method of delivery, controlling the amount of drug delivered to the site is challenging. If the drug is conveyed through a channel, it is difficult to ensure that contact between the drug and the disease is of adequate duration and intimacy to be effective. If the drug is applied onto the surface of the balloon, the drug gets washed away (at least partially) by various bodily fluids and/or fluids introduced procedurally during the navigation of the balloon to the site. Also, if the drug is applied onto the surface of the balloon, the drug coating may get scraped off by other devices or by bodily structures other than the site of disease. In any case, it is difficult to predict exactly how much drug is being delivered to the intended site and whether the dosage is sufficient. In the face of such uncertainty, the strategy typically employed is to use an overabundance of drug to accommodate the described losses in the hope that a successful therapeutic outcome results.
It is desirable to create a device that alleviates the challenges outlined above.